\psset{unit=0.7,algebraic}
\begin{pspicture*}(-3,-1)(3,4)
\psaxes[labelFontSize=\scriptstyle,ticksize=-3pt 0,labelsep=2pt]{<->}(0,0)(-3,-1)(3,4)
\psplot[linecolor=blue]{-3}{-0.01}{1/x^2}
\psplot[linecolor=blue]{0.01}{3}{1/x^2}
\end{pspicture*}